Electrochemical gas sensors are well known for detecting and quantifying toxic gases such as carbon monoxide, oxygen and the like. Such sensors can be implemented using electrochemical cells. Such cells operate in an amperometric mode providing a current output which is related to the concentration of the particular analyte gas.
Such sensors usually include a sensing electrode. Known electrodes are made by a solution-based method.
In such solution-based methods, a catalyst is initially ultrasonically dispersed in an aqueous solution to form a suspension. Polytetrafluoroethylene (PTFE) is added to the suspension for form a flocculate mixture. The flocculate mixture is then transferred onto a substrate, which is sintered at an elevated temperature. The sintered mixture is then transferred onto a microporous PTFE membrane, then pressed. The ratio of PTFE in the electrode not only affects gas diffusion parameters in the sensor, it also supports the electrocatalyst and maximizes the interfaces between catalyst, gas and electrolyte at which the key electrochemical processes occur.
As is apparent, many steps are needed in this solution-based method to manufacture an electrode. The consequences include high manufacturing costs, material costs and labor costs.